/**
 * AnyStream
 * Copyright (C) 2021 AnyStream Maintainers
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package anystream.util

import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.async
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.buffer
import kotlinx.coroutines.flow.map

fun <T, R> Flow<T>.concurrentMap(
    scope: CoroutineScope,
    concurrencyLevel: Int,
    transform: suspend (T) -> R,
): Flow<R> = this
    .map { scope.async { transform(it) } }
    .buffer(concurrencyLevel)
    .map { it.await() }
